000
AXNT20 KNHC 311044
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI JUL 31 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1045 UTC.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 43W TO THE SOUTH OF 22N 
MOVING WEST ABOUT 20 KT. THE POSITION WAS MOVED A BIT MORE TO 
THE WEST IN ORDER TO AGREE MORE WITH THE SHORTWAVE INFRARED 
SATELLITE IMAGERY. NO DEEP CONVECTIVE PRECIPITATION.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 70W TO THE SOUTH OF 20N
MOVING WEST ABOUT 20 KT. ISOLATED MODERATE SHOWERS ARE FROM 14N
TO 22N BETWEEN 68W AND 74W.

...THE ITCZ...

FROM THE AFRICA COAST NEAR 14N17W TO 11N30W TO 11N41W 10N50W
TO TRINIDAD/EXTREME NORTHEASTERN VENEZUELA. ISOLATED MODERATE 
SHOWERS AND POSSIBLE THUNDERSTORMS ARE WITHIN 60 NM OF THE COAST 
OF AFRICA FROM 8.5N TO 14.5N...AND WITHIN 60 NM TO 90 NM ON 
EITHER SIDE OF 12N23W 9N30W 9N42W 7N48W 8N55W...AND FROM COASTAL 
VENEZUELA TO 13N BETWEEN 63W AND 66W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL TROUGH GOES FROM 28N86W TO 24N93W TO 21N100W
IN MEXICO. THIS TROUGH IS SURROUNDED BY UPPER LEVEL DRY AIR.
UPPER LEVEL MOISTURE MOVES SOUTHWESTWARD FROM THE ATLANTIC 
OCEAN...CROSSING 30N TO THE WEST OF 75W/76W TOWARD FLORIDA AND 
THE STRAITS OF FLORIDA...INTO THE GULF OF MEXICO TO 86W. BROAD 
UPPER LEVEL CYCLONIC FLOW COVERS MEXICO TO THE NORTH OF 21N.
A COLD FRONT MOVES FROM A POINT THAT IS A LITTLE BIT TO THE 
NORTHWEST OF LAREDO TEXAS...INTO MEXICO ABOUT 90 NM TO THE
SOUTH OF THE TEXAS BIG BEND AND THEN THE FRONT CURVES TO FAR 
WEST TEXAS NEAR EL PASO. SCATTERED MODERATE SHOWERS TO ISOLATED 
STRONG THUNDERSTORMS ARE TO THE NORTH OF 24N TO 26N BETWEEN
102W AND 105W.

THE CARIBBEAN SEA...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM THE ATLANTIC 
OCEAN NEAR 30N70W TO 26N74W TO SOUTHEASTERN CUBA NEAR 20N78W TO
17N86W TOWARD THE GULF OF HONDURAS. ISOLATED SHOWERS HAVE POPPED 
UP FROM HAITI TO THE WATERS BETWEEN CUBA AND THE CAYMAN ISLANDS.
THE SOUTHERN END OF AN UPPER LEVEL TROUGH FROM 31N57W IN THE 
ATLANTIC OCEAN REACHES NEAR 17N66W JUST TO THE SOUTH OF PUERTO 
RICO. A TROPICAL WAVE THAT IS ALONG 70W IS SPREADING ISOLATED 
MODERATE SHOWERS FROM 14N TO 22N BETWEEN 68W AND 74W. MOST OF
THE PRECIPITATION FROM SIX HOURS AGO THAT COVERED THE AREA FROM 
MEXICO TO EL SALVADOR AND NICARAGUA HAS MOVED OFFSHORE INTO
THE EASTERN PACIFIC OCEAN. ISOLATED MODERATE SHOWERS AND
THUNDERSTORMS COVER CENTRAL AMERICA FROM HONDURAS THE WATERS
TO THE EAST OF NICARAGUA FROM 12N TO 14N BETWEEN 80W AND 
NICARAGUA. THIS PRECIPITATION WAS OCCURRING IN AN AREA OF UPPER 
LEVEL DIFFLUENT WIND FLOW. WARMING CLOUD TOP TEMPERATURES AND 
LINGERING SHOWERS AND THUNDERSTORMS FROM COASTAL COLOMBIA TO 
COASTAL PANAMA INCLUDING IN THE GULF OF URABA.

THE ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH EXTENDS FROM A 31N57W CYCLONIC CIRCULATION 
CENTER TO 27N57W 25N61W 23N63W 20N64W INTO THE CARIBBEAN SEA 
NEAR 17N66W JUST TO THE SOUTH OF PUERTO RICO AND THE VIRGIN 
ISLANDS. POSSIBLE SHOWERS ARE WITHIN 120 NM TO THE NORTH OF
THE 31N57W CYCLONIC CENTER AND WITHIN 60 NM TO THE SOUTH OF IT.
AN UPPER LEVEL TROUGH PASSES THROUGH 33N28W TO 30N37W 28N38W
TO 24N46W. A SEPARATE UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC 
CIRCULATION CENTER NEAR 28N45W TO 25N50W. AN EASTERN ATLANTIC 
OCEAN UPPER LEVEL TROUGH IS ALONG 18N17W 22N20W TO 25N24W
WITHOUT ANY DEEP LAYER CONVECTIVE PRECIPITATION. 

$$
MT